Ferromagnetic materials can have magnetostrictive properties that can cause the materials to change shape in the presence of an applied magnetic field. The inverse is also true. When a force is applied to a conductive material, magnetic properties of the material, such as magnetic permeability, can change. A magnetostrictive sensor can sense the changes in magnetic permeability and, because the changes can be proportional to the amount of stresses applied to the conductive material, the resulting measurement can be used to calculate the amount of stress.
However, magnetostrictive sensors can be sensitive to a separation distance between the sensor and a target material.